JPH0459889A - Production of soil conditioner from slag - Google Patents

Abstract

PURPOSE:To easily obtain a soil conditioner having high water-absorption and capable of neutralizing acid soil and keeping the activity of agricultural chemicals over a long period by baking a mixture composed of refractory clay and finely crushed iron or steel slag and slowly cooling the product. CONSTITUTION:The objective conditioner can be produced by baking a mixture composed of (A) 15-30wt.% of refractory clay and (B) the remaining part of finely crushed iron or steel slag at about 900-1050 deg.C and slowly cooling the mixture so as not to vitrify the surface of the product. When the component B is a slag containing only a small amount of gas-generation component such as iron oxide, it may be added with <=5wt.% of a pore-forming organic material such as sawdust.

Description

[Detailed description of the invention] <Industrial application field> The present invention is currently not fully utilized in steel manufacturing.

This invention relates to a method for effectively utilizing steelmaking slag to create a soil improvement material.

<Prior Art> Recently, various types of natural destruction have become a problem, such as damage to plants due to acid rain and damage caused by pesticides on golf courses.

On the other hand, iron and steelmaking slag are not fully utilized, and there are currently problems with where to dispose of them.

However, as shown in Table 1 below, these slags mainly contain two components: lime and silicic acid, and also contain other components that are effective for plant growth, such as alumina, magnesia, iron, and manganese. Very few are harmful.

In the first expression, these slags are currently pulverized and used as silica fertilizer, by-product lime, etc.

However, as noted in Table 1 above, these slags have the disadvantage that their fertilizing effect is not fully demonstrated because they have low water absorption and lack water retention.

<Problems to be Solved by the Invention> As mentioned above, the present invention is a porous ceramic material for slag that contains effective ingredients for plant growth, but cannot effectively utilize them due to its water retention properties. The purpose is to provide a soil improvement material that has high water retention properties as a whole by combining the following.

<Means for Solving the Problems> The above object of the present invention can be solved by the following means. That is, this is a method for producing a soil improvement material from slag, in which a mixture consisting of 15 to 30% by weight of fireclay, the remainder finely pulverized iron, and steelmaking slag is fired, and then slowly cooled.

Here, if the slag used contains a large amount of components that generate gas during firing, such as iron oxide, only fireclay may be used as the substance to be mixed with the slag, but slag that does not contain much gas-generating components such as iron oxide may be used. In this case, 5% by weight of organic matter (such as sawdust) that forms bores after firing.
It may be added in the following range.

Adding fireclay in the range of 15 to 30% by weight is 1
This is because if it is less than 5% by weight, the product lacks caking properties and is likely to become powdered during handling up to firing, while if it exceeds 30% by weight, the amount of slag will be too low and the water absorption will be too small.

The firing conditions are generally 900 to 1050"C, depending on the slag components and the mixing ratio of other substances.
The subsequent cooling is carried out gradually so that the surface of the product does not become glassy.

Effect> In the present invention, fireclay alone or fireclay and organic matter are added to slag and fired, so that the organic matter is naturally contained in the slag and fireclay.

The traces of the gasified components released form countless fine pores, the slag itself expands, and the resulting product becomes a type of porous ceramic containing a large amount of lime.

Therefore, its absorption rate is 30 to 41%, which is extremely high in water absorption compared to the 1.0 to 6.0% of boat fishing slag as shown in Table 1 above.

The lime content (Cab) of the obtained product is 25 to 35% by weight.
This is sufficient as an alkaline fertilizer.

<Example> Examples of the present invention will be shown below.

This example contains 68% by weight of electric furnace slag and 27% by weight of this clay.
% by weight and 5% by weight of sawdust as organic matter were mixed and held at 1000° C. for 30 minutes in an electric furnace, and then slowly cooled. .

The water absorption rate of the obtained product was 40.8%, and the apparent porosity was 55.
．． 9%, and the bulk specific gravity was 1.37.

<Effects of the Invention> As described above, according to the present invention, fireclay or fireclay and an organic substance are added to iron and steelmaking slag, which has not been used effectively in the past, by a simple operation of slowly cooling after firing. A product with high water absorption can be obtained, and it is possible to neutralize acidic soil and maintain the effects of agricultural chemicals over a long period of time. Therefore, it has the effect of reducing the number of times pesticides are used and reducing the damage caused by pesticides.

In addition, since the product obtained by the present invention is porous, it adjusts the moisture and dryness of the soil and acts as a carrier for the growth of microorganisms in the soil, so it works synergistically with the fertilizing components of the slag, making the soil suitable for plant growth. It also has the effect of maintaining optimal conditions.

Patent Applicant: Izumiyama Seido Co., Ltd. Representative: Noriyoshi Ariyoshi Haruyuki August 1990
29th of the month

Claims (1)

[Claims] 1. 15 to 30% by weight of fireclay, the balance being finely pulverized iron,
A method for producing a soil improvement material from slag, which comprises firing a mixture of steelmaking slag and then slowly cooling it. 2. Fireclay 15-30% by weight, organic matter 5% by weight or less (
A method for producing a soil improvement material from slag, which comprises firing a mixture consisting of iron and steelmaking slag (excluding 0), the remainder being finely pulverized, and then slowly cooling the mixture.